There exists a variety of facilities to process raw materials in one or more unit operations to produce one or more products.
For instance, in a hydrogen-carbon monoxide plant, natural gas is used both as a reactant feed along with steam to a steam methane reformer and as a fuel for burners that support the endothermic steam methane reforming reaction. Steam methane reforming produces a synthesis gas product that contains carbon monoxide, carbon dioxide and hydrogen. In subsequent operations, the synthesis gas is processed by an amine scrubbing unit to remove carbon dioxide. After carbon dioxide removal, carbon monoxide is separated to produce a crude hydrogen stream. Additionally, part of the synthesis gas product from the steam methane reforming is subjected to water gas shift reaction to produce a shifted gas stream that is combined with the crude hydrogen stream and further processed within a pressure swing adsorption unit to produce hydrogen and a purge gas that can be recirculated as part of the fuel to fire the burners of the steam methane reformer. Additionally, some of the shifted gas along with syngas, carbon dioxide and hydrogen can be processed in a methanol plant to make methanol. Some of the methanol can be further processed to make formaldehyde.
In another type of facility, air is separated into oxygen, nitrogen and argon products. In such a facility, the air is compressed, cooled to at or near its dew point and fractionated within the higher and lower pressure columns to produce a nitrogen product and an oxygen product.
In all of such facilities, unit operations are conducted by automated control systems that can set targets for the operations and adjust controls as necessary for the facility to meet the targets. Therefore it becomes necessary for operational staff to have an indication as to the performance of the plant. One way of monitoring the performance of the plant is to monitor the reaction of the plant to control inputs in which targets are set. For instance, in U.S. Pat. No. 6,666,049, a control system utilizes models to determine optimal values of such key performance indictors as plant power consumption, product recovery, controller performance, model predictive controller steady state optimization, model prediction of models utilized by the model predictive controller and model predictive control dynamic performance. Each of these key performance indicators are monitored and operational personnel are alerted when a key performance indicator is outside of a determined expected optimal value range for the specific performance indicator. The system also can suggest one or more actions to the plant operator for adjusting the operation of a cryogenic plant so that a value of a key performance indicator that is outside of the expected range can be brought back into the expected range.
This type of monitoring, while important, does not provide an operator of an instantaneous view of the overall performance of the plant. As will be discussed, the present invention provides a monitoring method that can be applied to any type of facility in which the overall performance of the plant is monitored.